Self-Consistent Determination of Time-Dependent Behavior of Metals

1981 ◽  
Vol 48 (1) ◽  
pp. 41-46 ◽  
Author(s):  
G. J. Weng
Keyword(s):  
Driving Forces ◽  
Pure Shear ◽  
Time Dependent ◽  
Hardening Law ◽  
Dependent Behavior ◽  
Consistent Model ◽  
Self Consistent ◽  
The Matrix ◽  
Latent Hardening

Though Kro¨ner’s self-consistent model is not fully consistent in the elastic-plastic deformation of polycrystals, it is found to be perfectly consistent in the time-dependent deformation of such materials. Hill’s model, on the other hand, should be used with a modified constraint tensor containing the elastic moduli of the matrix in that case. Kro¨ner’s model is supplemented with a physically consistent constitutive equation for the slip system; these, together with Weng’s inverse method, form the basis of a self-consistent determination of time-dependent behavior of metals. The kinematic component of the latent hardening law and the residual stress introduced in more favorably oriented grains are the two major driving forces for recovery and the Bauschinger effect in creep. The proposed method was applied to predict the creep and recovery strains of a 2618-T61 Aluminum alloy under pure shear, step and nonradial loading. The predicted results are seen to be in generally good agreement with the test data.

scholarly journals Eshelby-Kröner Viscoelastic Self-Consistent Model Multi-Scale Behavior of Polymer Composites under Creep Loading

2013 ◽  
Vol 682 ◽  
pp. 105-112 ◽  
Author(s):  
A. Yousfi ◽  
Sylvain Fréour ◽  
Frédéric Jacquemin
Keyword(s):  
Mechanical Properties ◽  
Mechanical Response ◽  
Effective Properties ◽  
Time Dependent ◽  
Creep Process ◽  
Internal Stresses ◽  
Temperature Range ◽  
Consistent Model ◽  
Self Consistent ◽  
Different Temperatures

The mechanical response of the composite structure in T650-35/PMR-15 aged at different temperatures was studied numerically. The time-dependent internal stresses in the composite ply and its constituents were computed during the creep process. In order to predict the effective properties of PMR-15/T650-35 composite ply in the temperature range [250-350°, the time-dependent mechanical properties of PMR-15 matrix determined experimentally [, were considered. The mechanical properties of the fibers do not experience any change due to the aging process in such a temperature range [2, . In order to achieve the computations, the visco-elastic Eshelby Kröner self-consistent model was used.

The Indentation Elastic Response - Indentation Shape and the Stress Distribution

1994 ◽  
Vol 356 ◽  
Author(s):  
B. C. Hendrix ◽  
Ke-Wei Xu ◽  
Jun-Hai Liu ◽  
Jia-Wen He
Keyword(s):  
Elastic Recovery ◽  
Transversely Isotropic ◽  
Elastic Response ◽  
Consistent Model ◽  
Self Consistent ◽  
Unique Model ◽  
Transversely Isotropic Materials ◽  
Fundamental Value ◽  
Further Development

AbstractThe unloading of an indentation provides information about the shape of the indentation and the elastic properties of the materials. The assumptions of axisymmetry and material isotropy are critically examined, and a model for transversely isotropic materials is compared to measurements on single crystals. The methods used to infer the area of the indentation from the unloading curve are examined. The area is a fundamental value for the determination of hardness, modulus, and other mechanical properties in the so-called nano-indentor and other continuously monitored indentor techniques. The models of elastic recovery which are currently used are found to lack the flexibility to model the parameters which determine indentation depth. If the current self-consistent model is extended to cover the important aspects of the unloading, the area of the indentation is still not determined uniquely. Guidelines for further development of a unique model are suggested.

Incompatibility Stresses and Elastic Energy Stored in Polycrystalline Materials

2010 ◽  
Vol 638-642 ◽  
pp. 3827-3832 ◽  
Author(s):  
Andrzej Baczmanski ◽  
Roman Wawszczak ◽  
Wilfrid Seiler ◽  
Chedly Braham ◽  
S. Wroński ◽  
...  
Keyword(s):  
Stress Field ◽  
Elastic Energy ◽  
Ferritic Steel ◽  
Diffraction Method ◽  
Polycrystalline Materials ◽  
Consistent Model ◽  
Self Consistent ◽  
Euler Space ◽  
Cold Rolled

ray diffraction method is used to determine the stress field in polycrystalline materials. The measurement of peak shifts enables the determination of the macrostresses and the plastic incompatibility stresses (intergranular stresses). In the interpretation of the experimental results self-consistent model of elatoplastic deformation is used. In the present work, the plastic incompatibility stresses and the elastic energy stored in cold rolled brass and ferritic steel were determinate. The results are discussed and presented in Euler space.

Mesoscale Simulation of Uniaxial Tension of FCC Polycrystal Using Viscoplastic Self Consistent Method

2011 ◽  
Vol 87 ◽  
pp. 71-77
Author(s):  
Fu An Hua ◽  
Jian Ping Li ◽  
Wu Di ◽  
Guo Dong Wang
Keyword(s):  
Tensile Deformation ◽  
Isotropic Hardening ◽  
Mesoscale Simulation ◽  
Grain Rotation ◽  
Hardening Law ◽  
Consistent Model ◽  
Self Consistent ◽  
Theoretical Predictions ◽  
Consistent Method ◽  
Simulation Results

A viscoplastic self consistent model was developed using a rate sensitive constitutive relation, isotropic hardening law, and considering the interaction between the grains and their surroundings. The model was applied to simulate the mesoscopic responses of fcc polycrystalline aggregate during tensile deformation. The macro textures, the grain rotation behaviors, plastic strain and stress heterogeneities, and slip system activities were investigated. The model successfully predicts the typical tensile textures, the grain rotations toward (111) and (100) directions and the orientation dependent slip activities, etc. The simulation results are qualitatively in agreement with experimental measurements and theoretical predictions.

scholarly journals Macromolecular structure and viscoelastic response of the organic framework of nacre in Haliotis rufescens: A perspective and overview

2011 ◽  
Vol 38 (2) ◽  
pp. 75-106 ◽  
Author(s):  
Jiddu Bezares ◽  
Zhangli Peng ◽  
Robert Asaro ◽  
Qiang Zhu
Keyword(s):  
Time Dependent ◽  
Macromolecular Structure ◽  
New Paradigm ◽  
Independent Measurement ◽  
Material Models ◽  
Haliotis Rufescens ◽  
Dependent Behavior ◽  
Structural Composite ◽  
Constitutive Parameters

Nanoindentation probing on nacre obtained from Haliotis rufescens shells has demonstrated that nacre displays a combined viscoplastic-viscoelastic time dependent response. Additionally, it is found that the moisture/water content of nacre contributes to its time dependent behavior and overall mechanical properties. Detailed finite element simulations allow for the determination of constitutive parameters used to calibrate specific time dependent material models which are, in turn, compared to those found via independent measurement as reported in the literature. The results lead to a new paradigm for nacre?s attractive structural composite behavior and thereby to new potential pathways for biomimetics.

Modeling the Anisotropic Finite-Deformation Viscoelastic Behavior of Soft Fiber-Reinforced Tissues

2007 ◽  
Author(s):  
Thao D. Nguyen ◽  
Reese E. Jones ◽  
Brad L. Boyce
Keyword(s):  
Viscous Flow ◽  
Finite Deformation ◽  
Composite Structures ◽  
Volume Fraction ◽  
Viscoelastic Behavior ◽  
Time Dependent ◽  
Flow Rule ◽  
Fiber Reinforced ◽  
Dependent Behavior ◽  
The Matrix

This paper presents a constitutive model for the anisotropic, finite-deformation viscoelastic behavior of soft fiber-reinforced tissues. Soft fiber-reinforced tissues, such as the cornea, tendons, and blood vessels, have a unique combination of mechanical properties that enables them to perform important structural, protective, and energy-absorbing functions. Because of their fiber-reinforced microstructure, these tissues are extraordinarily stiff and strong for their weight. Many are also flexible and tough. The toughness of these tissues arises from the ability of both the soft fiber and matrix phases to dissipate energy through large viscoelastic deformations. The viscoelastic behavior of the matrix of soft tissues can arise from fluid flow through a swollen polymer network and/or the diffusive motion of polymer segments within the network. The time-dependent behavior of the fiber reinforcements, which themselves can be composite structures, stems from the viscoelastic nature of the fiber material and/or the dissipative mechanisms of the fiber/matrix interface. To model the distinct time-dependent behavior of both fiber and matrix constituents, the tissue is represented as a continuum mixture consisting of a variety of fiber families embedded in an isotropic matrix. Both phases are required to deform with the continuum deformation gradient. However, the model attributes a different viscous stretch measure and free energy density to the matrix and fiber phases. Separate viscous flow rules are specified for the matrix phase and the individual fiber families. The flow rules for the fiber families are combined to give an anisotropic effective viscous flow rule for the fiber phase. An attractive feature of model is that key parameters can be related to the material properties (i.e., moduli, viscosities, volume fraction) of the fiber and matrix phases. Also, the anisotropy exhibited by both the elastic and viscous response of the composite arises directly from the fiber arrangement.

A self-consistent model for the particles and fields upstream of an outgassing comet: 2. A time-dependent description

1992 ◽  
Vol 97 (A6) ◽  
pp. 8173 ◽  
Author(s):  
K. Flammer ◽  
T. E. Birmingham ◽  
D. A. Mendis ◽  
T. G. Northrop
Keyword(s):  
Time Dependent ◽  
Consistent Model ◽  
Self Consistent

Further Investigation of a New Hardening Law in Crystal Plasticity

1978 ◽  
Vol 45 (3) ◽  
pp. 500-506 ◽  
Author(s):  
K. S. Havner ◽  
A. H. Shalaby
Keyword(s):  
Face Centered Cubic ◽  
Slip Systems ◽  
Anisotropic Hardening ◽  
Active System ◽  
Cubic Crystals ◽  
Hardening Law ◽  
Crystallographic Symmetry ◽  
Latent Hardening ◽  
Face Centered

A simple theory of latent hardening in crystals, recently proposed by the authors [1], is applied to the determination of anisotropic hardening in slip systems of face-centered cubic crystals in the tensile test, based upon a parabolic resolved-shear-stress versus slip curve in the active system. The theory predicts the generally observed continuation of finite single slip beyond the crystallographic symmetry line. Moreover, the predicted diversity of finite distortional hardening among latent slip systems is in qualitative agreement with experiment.

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